Inside Unmanned Systems

AUG-SEP 2018

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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AIR HAZARD LOCATION
60 August/September 2018 unmanned systems
inside
but each has a different number of neutrons—for
instance, uranium-235 has 143 neutrons, while
uranium-238 has 146.)
The kind of nuclear chain reactions that both
nuclear reactors and nuclear weapons depend on
are possible with uranium-235 but not with ura-
nium-238. During the Cold War, uranium enrich-
ment plants often forced a gas of uranium-laden
molecules through membranes that could separate
the lighter uranium-235 from the heavier ura-
nium-238, resulting in "enriched" uranium with
high concentrations of uranium-235. This process
typically left deposits of radioactive waste clinging
to the insides of miles of the plants' "process pipes."
"These deposits almost look like a thin layer
of paint inside the piping," said William "Red"
Whittaker, a robotics professor and director of
the Field Robotics Center at Carnegie Mellon
University in Pittsburgh. "This material is de-
posited during a chemical reaction with the ura-
nium-laden gas with water or something else that
would provide oxygen."
Whittaker and his colleagues have now built an
autonomous robot called RadPiper to help detect
this hazardous nuclear waste at the Department
of Energ y's 3,778-acre Portsmouth Gaseous
Diffusion Enrichment Facility in Piketon, Ohio.
Shuttered since 2000, this plant began opera-
tions in 1954, and with 10.6 million square feet
of f loor space, it was the Department of Energy's
largest roofed facility. Three large buildings con-
tain enrichment process equipment that spans an
areas the size of 158 football fields and contains
more than 75 miles of process pipe.
Locating the nuclear waste throughout the
huge facility is a herculean but essential task
before the Department of Energy can decon-
taminate, decommission and demolish it. In the
Portsmouth plant's first process building alone,
human crews performed more than 1.4 million
measurements of processing piping and compo-
nents manually over the past three years before
they could declare the building "cold and dark."
The next process building has more than 15 miles
of piping that needs scanning, which robots could
help with immensely, Rimando said.
Scientists at Carnegie Mellon University were
paid $1.4 million to build RadPiper as part
of what the university calls the Pipe Crawling
Activity Measurement System. The researchers
developed the robot in close collaboration with
Fluor-BWXT Portsmouth, the contractor that
the federal government hired to decommission
the Portsmouth facility.
Whittaker has a great deal of experience with ro-
bots in nuclear facilities, including the design and
construction of robots that helped gather data and
remove debris after the partial meltdown at the
Three Mile Island reactor building in Pennsylvania
in 1979. He and his colleagues also developed ro-
bots to help with inspections in the aftermath of the
Chernobyl disaster in Ukraine in 1986.
The conventional technique for identifying hid-
den deposits in process pipes involves people with
handheld radiation detectors scanning process
pipes from the outside in search of the gamma
rays from radioactive isotopes. However, "since
you're measuring from the outside, those gamma
rays can be attenuated by the pipes themselves,"
Rimando said.
This method is time-consuming and labor-
intensive. "You have to hold the detector outside
the pipe for at least 30 seconds before you move a
foot or so further down to measure the next seg-
ment," Rimando said. "And many of these pipes
are overhead, and normally need a scissor lift or
some other platform to access, and as you move
down a pipe, you'll need to move the scissor lift
to a new location as well. Logistically, there may
also be issues getting a lift in certain places in a
building, and the stanchions and brackets hold-
ing up the pipes can be very difficult to maneuver
around as well."
" FOR EVERY EIGHT HOURS OF CONDUCTING
SURVEYS WITH HANDHELD EQUIPMENT, RADPIPER CAN DO IT IN AN
HOUR, AND THAT EIGHT-TO-ONE RATIO IS LIKELY AN UNDERESTIMATE."
Rodrigo Rimando, director of technology development,
U.S. Department of Energy, Office of Environmental Management
RADIION
CLEANUP